Handle `CSI u` Input (aka fixterms)

[meowgorithm]

It would be nice for Bubble Tea to support the "CSI u" Encoding Specification as outlined in Paul Evans' seminal work "Fix Keyboard Input on Terminals - Please".

References:

• Wezterm
• Kitty
• Windows Terminal
• iTerm2

Special thanks to @imsnif for the suggestion.

[ghostsquad]

Yes please!